How hot? The heat index - which combines heat and humidity - may hit 165 to 170 degrees for at least six hours, according to numerous computer simulations in the new study published on Monday in the journal Nature Climate Change.
That's so hot that the human body can't get rid of heat. The elderly and ill are hurt most by current heat waves, but the future is expected to be so hot that healthy, fit people would be endangered, health experts say.
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